The DDoS attack that is one of the most threatening attacks in the wired network has been already extended in the wireless mobile network, owing to the appearance of DDoS attack tool against mobile phone. In the future, the latent threats for DDoS attacks should be resolved for the induction of successful convergence network. However, due to the current problems to defend them, such as the absence of the converged defense or internetworking between each defense system, the research for cooperation architecture between them allowing each defense process is indispensable. In this paper, we propose a scalable defense architecture based on overlay routing against DDoS attacks in consideration of the capacity of each node, providing speedy notification of attack detection on converged network and detouring of the normal packets before the fundamental exclusion of attack agents. Our simulation results show that our architecture provides the speedy notification and decreases the damage of normal traffic even in the form of converged DDoS attacks.